Well if I was offered a 1000 grams female that has been bred I would pass regardless of the criteria I recently mentioned here Breeding size help?
Either he breeds his animals carelessly at a size far from being optimum which as Lee mentioned will not likely result in good outcomes (extremely small clutch or slugs being the most likely) which means the animal would have to get the following season off and not be bred by you before 2022 (might better off getting a sub adult now to do that).
Or he breeds an animal on the very small side that is older than 4 years and do so because she has the age but not the size however this is usually the result of an animal being a finicky eater if barely around a 1000 grams at 4 years or more which may or not be solved once she lays. Sometime it kickstart their appetite and they start eating normally and catch up but sometime they don’t that’s a huge gamble.